noun
isosceles trapezoid; isosceles trapezium
A trapezoid with congruent base angles and equal-length legs. Used in geometry.
等脚台形の底角は等しい。
The base angles of an isosceles trapezoid are equal.
この図形は等脚台形です。
This shape is an isosceles trapezoid.
台形 is a general trapezoid; 等脚台形 specifies an isosceles trapezoid with equal legs and base angles.
Compound of 等脚 (isosceles) and 台形 (trapezoid). The term is a direct calque from English 'isosceles trapezoid'.